C#红绿状态灯

1.在Label里 画圆，存在窗体刷新会丢失画。

  public void SetShowConnectStatus(Label lbl, bool isOk)
        {
            lbl.Text = "";
            Graphics gra = lbl.CreateGraphics();
            gra.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
            Color c = isOk ? Color.Green : Color.Red;
            Brush bush = new SolidBrush(c);//填充的颜色
            gra.FillEllipse(bush, , , lbl.Width / , lbl.Width / );

        }

2.在控件Paint事件里画，Invalidate 刷新。

  private bool isRotaryConnectOK = false;
        private void button1_Click(object sender, EventArgs e)
        {

            isRotaryConnectOK =!isRotaryConnectOK;
            lblRotaryConnectStatus.Invalidate();
        }

        private void lblRotaryConnectStatus_Paint(object sender, PaintEventArgs e)
        {
            Graphics gp = e.Graphics;
　　　　　　　gp.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
            Color c = isRotaryConnectOK ? Color.Lime : Color.Red;
            SolidBrush s = new SolidBrush(c);
            gp.FillEllipse(s, , , lblRotaryConnectStatus.Width/, lblRotaryConnectStatus.Width / );
        }

void FillEllipse(Brush brush,int x,int y,int width,int height);
其中brush为指定画刷，(x1,y1)为指定矩形的左上角坐标，width为指定矩形的宽，height为指定矩形的高。

添加文字：

Font font_ = new Font("微软雅黑", 14, FontStyle.Regular);
SolidBrush brush_ = new SolidBrush(Color.White);
gp.DrawString(adcLsbNumber_, font_, brush_,8, 6);